1. Field of the Invention
The present invention pertains to a liquid removal system for removing liquids from within a second object, and particularly to a system for removing water from the interior of a gas main.
2. Description of the Related Art
It is frequently desired to remove waste liquids from the interior of a container or conduit. For example, in a gas pipeline, water often collects at low points in the pipeline. The water may have been introduced by damage to an adjacent water main, or may have been introduced by rehydration of water vapor within the natural gas. Regardless of the method of introduction, the presence of water is undesired since it can prevent the flow of the gas product through the pipeline. The flow of gas is particularly restricted during winter months when the water freezes.
It is, accordingly, necessary to remove the water from time to time. Preferably, the water would be removed without disconnecting the gas service. Moreover, in the case where the gas main has been buried, the number of excavation sites should be minimized.
It has hitherto been suggested to remove water from the gas main by snaking a secondary pipe through the gas main to low points in the main where water has collected. Thus, U.S. Pat. No. 3,756,266 suggests a system wherein a pipe of diameter smaller than that of the gas main is fed to the low point in the gas main. Water within the gas main is forced through minute holes placed longitudinally in the pipe by pressure of the gas in the gas main. Water is propelled through the small pipe and subsequently expelled at the opposite end thereof. Caster assemblies are provided at intervals on the small pipe to allow the pipe to be positioned easily within the gas main.
However, the device in the the above-described patent illustrates the shortcomings of prior art techniques for water removal. These techniques typically utilize a single element to perform both the water removal function and the snaking function. Requiring a single element to perform two functions places on this element the inconsistent constraints of being at once flexible enough to snake around interior bends in the gas main, yet stiff enough to be propelled through the main. In fact, in the above-described patent, snaking is impossible due to the rigidity of the inserted pipe. Accordingly, prior art techniques are unsuitable for most water removal applications, and particularly unsuitable for those applications where the gas main is buried within city streets and consequently includes a multitude of bends.